Ahmedabad: Gujarat Chief Minister Narendra Modi on Friday joined a protest against the Centre's move to block certain 'hate' pages and Twitter accounts by turning on his display picture to 'black', while terming the action as a "crackdown on freedom of speech".

"As a common man, I join the protest against crackdown on freedom of speech! Changed my DP. 'Sabko Samnati De Bhagwan' (May God give wisdom to all)," he posted on #GOIBlocks.

Twitter account holders in the country have started a movement against the Centre's reported move to block 300 web pages, including some Twitter handles, in the wake of Assam violence.

As a mark of their protest many netizens have joined '#GOIBlocks' which is trending (bulletin board where everybody can express their opinion on the subject) on Twitter.

Instead of Modi's image, the picture display section on his Twitter account today showed a blank space, along with the message denouncing the Centre's move to "muzzle" social media.

As per rough estimates, there are around 40 million Facebook and 16 million Twitter users in India.

The Union government has decided to block 300 web pages saying they posed a threat to national security.

According to reports, certain Twitter accounts being blocked by the Centre belonged to some RSS affiliates and leaders.

What prompted the Centre to step in is the 'provocative' mobile phone text messages being in circulation and doctored website images about Assam and Myanmar violence going viral, resulting in exodus of northeast people from some states fearing attacks on them by Muslims.